Altered Functional Connectivity of Hippocampal Subfields in Poststroke Dementia

Zhiyong Zhao; Huaying Cai; Manli Huang; Weihao Zheng; Tingting Liu; Di Sun; Guocan Han; Linhui Ni; Yi Zhang; Dan Wu

doi:10.1002/jmri.27691

Altered Functional Connectivity of Hippocampal Subfields in Poststroke Dementia

J Magn Reson Imaging. 2021 Oct;54(4):1337-1348. doi: 10.1002/jmri.27691. Epub 2021 May 18.

Authors

Zhiyong Zhao¹, Huaying Cai², Manli Huang³, Weihao Zheng¹, Tingting Liu¹, Di Sun², Guocan Han⁴, Linhui Ni², Yi Zhang^{1

5}, Dan Wu¹

Affiliations

¹ Key Laboratory for Biomedical Engineering of Ministry of Education, Department of Biomedical Engineering, College of Biomedical Engineering & Instrument Science, Zhejiang University, Hangzhou, China.
² Department of Neurology, Neuroscience Center, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China.
³ Department of Psychiatry, The First Affiliated Hospital, Zhejiang University School of Medicine, The Key Laboratory of Mental Disorder's Management of Zhejiang Province, Hangzhou, China.
⁴ Department of Radiology, Neuroscience Center, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China.
⁵ Department of Neurology, The First Affiliated Hospital, Zhejiang University, Hangzhou, China.

PMID: 34002915
DOI: 10.1002/jmri.27691

Abstract

Background: The hippocampus (HP) plays a critical role in memory and orientational functions and is functionally heterogeneous along the longitudinal anterior-posterior axis. Although the previous study has reported volumetric atrophy in hippocampal subfields of patients with poststroke dementia (PSD), how the functional connectivity (FC) is altered in these subfields remains unclear.

Purpose: To examine the FC changes of the HP subfields in patients with PSD.

Study type: Prospective.

Population: Seventeen normal controls, 20 PSD, and 24 nondemented poststroke (PSND) patients.

Field strength/sequence: A 3.0 T/ T1-weighted imaging, resting-state functional and diffusion tensor imaging.

Assessment: We first segmented the HP using independent component analysis, and then used granger causality analysis to calculate the directed FCs (dFCs) between the subfields and the whole brain, and compared the dFCs among PSD, PSND, and controls.

Statistical tests: Student's t-test, chi-square test, one-way ANCOVA, multiple regression, support vector machine, multiple comparison correction, and reproducibility analysis. A P value < 0.05 was considered statistically significant.

Results: Our results showed HP was functionally divided into HP_head , HP_body , and HP_tail bilaterally along the longitudinal axis. PSD patients showed significant dementia-specific decreases in the inward information flow and increases in the outward information flow associated with the bilateral entire HP/HP_head and left HP_body (P < 0.05). Moreover, we observed significant correlations (P < 0.05) between the cognition score and the dFCs related to the bilateral entire HP and left HP_head in the PSD group. Furthermore, dFCs of the HP and its subfields improved the classification between the PSD and PSND patients (accuracy/sensitivity/specificity: 94%/95%/93%) compared to the clinical and demographic parameters alone.

Data conclusion: These findings suggest that altered transmission and reception of information in the HP. These alternations were specific to individual subfields in PSD patients and may offer insight into the neurophysiological mechanisms underlying PSD.

Evidence level: 1 TECHNICAL EFFICACY: Stage 2.

Keywords: dementia; functional connectivity; granger causality analysis; hippocampal subfields; independent component analysis; stroke.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Dementia* / diagnostic imaging
Diffusion Tensor Imaging*
Hippocampus / diagnostic imaging
Humans
Magnetic Resonance Imaging
Prospective Studies
Reproducibility of Results